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Discussion Starter #1
Are there any year 351w heads that flow better than others. Class rules dictate that I run stock heads and cast iron exhaust manifolds. This kind of eliminates using GT40's. The same question applies to the exhaust manifolds about years.
 

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Pre-76 heads have larger valves, but from what I understand, 69-70 heads flow the best. Factory shorty headers from a 5.0 mustang would be your best bet here short of finding a set of Hi-Po cast iron manifolds from a 65-66 mustang. The hi-po's are being repopped, but they're still expensive.
 

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Are you allowed to modify the heads at all? If not, make sure the heads dont have the egr humps in the exhaust. i have a set of D0OE's that have them, so you might have to find some C9's maybe?

What about Clevlend heads? Are those fair game?

_________________
-Walt-

1964 Comet 289 C4 daily driver
"These go to 11." -This is Spinal Tap

<font size=-1>[ This Message was edited by: dragman64 on 1/15/02 8:33am ]</font>
 

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Oh, could you extrude hone the manifolds? Maybe acid port -if you dont want them to know
 

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Discussion Starter #6
Thanks for the input. Of course the rules state no mods, and of course it's all subject to what an inspector will catch. Mods will happen but I want to start with the best baseline heads. I believe the issue with the GT40's is the required cast iron exhaust manifolds. Thanks for the input on those, I'll start hitting the bone yards. As far as the Clevelands go, it was something I wrestled with but because of the other class restrictions I figured the potential of the Cleveland would go unused.
 

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The exhaust manifolds off of a 69 cougar 351W are pretty decent looking.They're sort of like a shorty header but are cast.I imagine most 69 and 70 cougar-mustangs will have these.Do all your parts have to match the year of your block or can you mix and match as long as their stock ford parts?
 

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fxcomet,I THINK,all 351W's had the SAME valves even to this day!!PLEASE let me know something I don't!!Maybe a CLEVELAND 351 had different valves!!!!
 

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Discussion Starter #9
The years of the parts don't matter so long as they're factory parts. Thanks frdnut for the insight on the Cougar/Mustang manifolds. The rules are pretty limited, especially in the area of cam specs and compression but my experience building Stock Eliminator drag engines should prove helpful for this customers needs even if it is for circle track.
 

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On 2002-01-15 19:08, 331NosMustang wrote:
fxcomet,I THINK,all 351W's had the SAME valves even to this day!!PLEASE let me know something I don't!!Maybe a CLEVELAND 351 had different valves!!!!
Nope, The '76-77 up are essentially identical to 302 heads except for the headbolt size, but prior to that, they had slightly larger valves than the 5.0. I'm have '75 castings on my Comet and the stock valves were larger than my 289's. I used 351's because it was easier to put the 1.94/1.60's in 'em (less machining). I reserve the right to be wrong on the years on these but I'm pretty sure the change occured '76-77.
 

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On the exhaust manifold thing, you also might look into the same year midsize cars (fairlane/torino and their mercury sibs). The manifolds on my '69 351w are very similar to the old 289hipo pieces
 

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The rules I run with say stock unmodified heads too. I use GT40 heads off a 1993 Cobra and they pass tech with no problems. If anyone squaks you can point out the fact they have even smaller intake valves than what the Chevys use. All I've done to them is machine for screw in studs and guideplates, put in some good valves and springs. Until last year I had to run cast iron manifolds too. Some snooping around the junkyards got me some manifolds that look half decent. Some 351s used manifolds that are pretty long and look like they flow ok. If you can find some old 289 HiPo's apparently they are the ones to use.
What kind of intake do you run? Carb?
 

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According to my small block ford book the 351 heads became the same as 302 heads in 77. This means smaller valves and huge 69cc combustion chambers.I hear they make good door stops.
 

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ALL '77-up 351 and 302 heads are the same except for head bolt hole sizes. All '69-'74 351W heads have 1.84/1.54 valves and bigger intake ports with 60-62CC combustion chambers(production casting tolerances varried from one head to another). '75-'76 351W heads are the same basic castings but came with smaller 1.78/1.45 302 valves while retaing the same bigger intake ports and same combustion chambers. Starting in '77 they went to **** and killed the 351W. Remember the Lightenings of the '90s also used iron GT-40 heads so the '93 Cobras and the Lightenings of the '90s used the same GT-40 heads. Those would definitely be the ones to use with 2nd best being the '69-'74 351W heads.
 

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if can you use any yr 351w then the the GT40's are legal as well as a roller block.
The 1995 351w Cobra R Mustang used them. That bad boy could run 12's with slix and gears. To bad they didnt make a boat load of 351W powered 80's and 90's stangs
 

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The 69-70 heads have smaller 60.4cc chambers.
Use the GT-40 heads if you are serious. They are significantly better than any of the old heads. With the chevy guys using the new Vortec heads, you don't have a chance with the old units, and are still going to be outpowered with the GT-40's.

Be sure to use the hipo manifolds, or at least the "good" 351W units. They look very similar. I believe some of the old FE powered trucks used the largest 2bbls. You might want to do some "comparison shopping" among carbs. Compression is going to paramount. Make sure the pistons come right up to zero deck, and mill the heads (look into angle milling to get more cc's) as much as possible. You'll also want to run the distributer "locked out" at full advance all the time, or at least have a very quick curve for power off the turns.

Good Luck!
 

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Discussion Starter #18
Great stuff from all. Rules spec out for all to use Performer intakes, 9.5:1 compression, 2bbl. carb. cast iron exhausts, 1.84/1.54 valves, stock lift cam. Pretty tight stuff. What's the casting number on those GT40 heads? I guess the later GT40P heads require the factory Mustang headers. Do the early GT40's? I've ordered a set of 69-70 heads but because I need to build two engines I'd like to try the GT40's if the cast manifolds bolt up.
 

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hmmm, the lift only has to be stock on the cam?? i think you could figure out some sort of custom grind to make it scream.
 

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What do they call stock valve lift?
Where I run I have a .470 lift rule and had a cam ground for that. Can you get away with more duration than stock?
 
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